The present invention relates to magnetoresistive heads and more particularly to a method and system for improving the stability of a MR head.
Conventional magnetoresistive (MR) heads use a MR element to sense the magnetization of bits in a track being read by the head. The MR element in the conventional MR head may include either an an isotropic magnetoresistive (AMR) element or a giant magnetoresistive (GMR) element. In either case, the MR element is magnetically biased. Typically, a conventional hard magnetic layer is used to bias the MR element. Typically, the hard magnetic layer includes cobalt-chrome-platinum. The MR head also includes leads for carrying current to and from the MR element. The leads are typically provided on the hard bias layer.
In order to provide the hard magnetic layer, a seed layer is provided. Typically, the seed layer is chromium. Thus, in the conventional MR head, the MR element is formed first. The seed layer is then deposited. The hard magnetic layer is then deposited on the seed layer. The magnetization of the hard magnetic layer can then bias the MR element.
Although the conventional MR head functions, the coupling between the hard magnetic layer and the MR element is reduced by the existence of the seed layer. Because of this, the MR element is more likely to include domain walls and, therefore, is more subject to noise.
Accordingly, what is needed is a system and method for providing a MR head having a magnetically stable MR element. The present invention addresses such a need.
The present invention provides a method and system for providing a stable magnetoresistive head. The method and system comprise providing a first gap and providing a seed layer. The seed layer is disposed above the first gap and has a space therein. The method and system further comprise providing a magnetoresistive element substantially covering the space in the seed layer and providing a hard bias layer above the seed layer. A portion of the hard bias layer is immediately adjacent to a portion of the magnetoresistive element.
According to the system and method disclosed herein, the present invention more strongly couples the hard bias layer to the magnetoresistive element, thereby increasing magnetic stability of the head and reducing noise due to domain wall motion. The noise is reduced because the seed layer is not present between the MR element and the hard bias layer.